Which statement is not true about the periodic table?
A. Elements in the same family have the same number of protons.
B. An element of the table is represented by a box with a symbol in it.
C. Elements in the same period of the periodic table have the same
number of electron shells.
D. It is organized by atomic number.

Answer:huh

Explanation:

Answer:

-Reversal of the resting potential due to influx of sodium ions

-Mechanism that restores the resting membrane voltage and intracellular ionic concentrations

-Period during which potassium ions are diffusing out of the neuron because of a change in membrane permeability

-A brief reversal of membrane potential that travels along the axon

Explanation:

An action potential is a situation where the membrane potential is briefly reversed from -70mV to +30 mV

There are three steps of the moving action potential, including;

1) The depolarization step, where the membrane resting potential is reversed by the rush of sodium ions into a neuron

2) The repolarization, due to the closing of the voltage-gated sodium channels and the opening of the potassium channels, which is a mechanism that restores the membrane's resting voltage and the ionic concentration in the cell

3) Hyperpolarization, where due to some open potassium channels, there is an increased potassium permeability, and excessive efflux of potassium ions take place, which results in a dip in the membrane potential

4) The above three phases describe the phase of the action potential which is the brief reversal of membrane potential that travels along the axon

Answer:

The frequency of a wave that has a wavelength of 28 m is 1.07*10⁷ Hz.

Explanation:

Wavelength is the minimum distance between two successive points on the wave that are in the same state of vibration. It is expressed in units of length (m).

Frequency is the number of vibrations that occur in a unit of time. Its unit is s⁻¹ or hertz (Hz).

The propagation speed is the speed with which the wave propagates in the medium, that is, it is the magnitude that measures the speed at which the wave's disturbance propagates along its displacement. Relate the wavelength (λ) and the frequency (f) inversely proportional using the following equation:

v = f * λ.

Being:

Replacing:

2.998*10⁸ m/s= f* 28 m

Solving:

[tex]f=\frac{2.998*10^{8}m/s }{28m}[/tex]

f= 1.07*10⁷ Hz

The frequency of a wave that has a wavelength of 28 m is 1.07*10⁷ Hz.

Answer:

When a mixture of water and alcohol boils, the vapors are a mixture of water vapor and alcohol vapor

Answer:

1. Mg (s) + 2Na+(aq) → 2Na(s) + Mg²⁺(aq)

2. 2K(s) + Cd²⁺(aq) → 2K⁺(aq) + Cd(s)

Explanation:

The net ionic equation of a reaction express only the chemical species that are involved in the reaction:

1. Mg (s) + Na2CrO4 (aq) → 2Na + MgCrO4(aq)

The ionic equation:

Mg (s) + 2Na+(aq) + CrO4²⁻ (aq) → 2Na + Mg²⁺ + CrO4²⁻(aq)

Subtracting the ions that don't change:

2. 2K(s) + Cd(NO3)2(aq) → 2KNO3(aq) + Cd(s)

The ionic equation:

2K(s) + Cd²⁺(aq) + 2NO3⁻(aq) → 2K⁺(aq) + 2NO3⁻(aq) + Cd(s)

Subtracting the ions that don't change:

Answer:

If there were multiple products, we can take each product and mixed with a sample of a pure compound that we suspect might be the same as the product. Then, we taking the melting point of this mixture that contains one of our product and pure sample. Then, we can observe the change in melting point, if there is no change in melting point or the melting stays in the same range of the pure compound. Then, the that product along with the pure sample are actually the same compound, not a mixture of two compounds. However, if the melting point for our pure sample compound changed or didn't stay in the same range after the mixing with on of our products. then we can conclude that this product and the pure sample are completely different compound, and indeed they are a mixture.

Answer:

See explanation

Explanation:

First we must obtain the limiting reactant. The equation of the reaction is;

CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g)

Number of moles of CH4= 28.6 g/16g/mol = 1.8 moles

Since the reaction is 1:1, 1.8 moles of CO2 was produced

Number of moles of O2 = 57.6 g/32 g/mol = 1.8 moles

2 moles of O2 produced 1 mole of CO2

1.8 moles of O2 produced 1.8 × 1/2 = 0.9 moles of CO2

Hence O2 is the limiting reactant

Mass of CO2 produced = 0.9 moles × 44 g/mol = 39.6 g

%yield = 32.1g/39.6 g × 100

%yield = 81.1%

According to the reaction equation;

2moles of O2 reacts with 1 mole of CH4

1.8 moles of O2 reacts with 1.8 × 1/2 =0.9 moles of CH4

Number of moles of CH4 left = 1.8 moles - 0.9 moles

Number of moles of CH4 left = 0.9 moles

Formula of xenon trioxide = XeO3

Relative atomic mass: Xe = 131.29, O = 16

Question 1

number of moles = mass / molar mass

n of XeO3 = 9.07 / 131.29 + 3(16)

= 0.05059 mol

number of moles = number of particle / Alvagadro's constant

0.05059 = number of molecule / 6.02 x 10²³

number of molecules = 3.046 x 10²²

Question 2

number of moles = number of particle / Alvagadro's constant

number of moles = 3.22 x 10²² / 6.02 x 10²³

number of moles = 0.05349 mol

number of moles = mass / molar mass

0.05349 = mass / 131.29 + 3(16)

mass = 9.590g

Answer:

Hi!

chemistry;

unlike others, is more about atomic structure.

HAVE A NİCE DAY

Explanation:

GREETİNGS FROM TURKEY ツ

Answer:

CHEMISTRY means the study of matter and the different chemical reactions that any substance goes through, like, matters composition, structure, shape, state, etc. while geology, biology and physics are the other branches of science and chemistry acts as a bridge between physics and geology with biology.

hope it helps

have a nice day

Answer:

18.5g Na2CO3

Explanation:

Chromium (III) chloride, CrCl3, reacts with Na2CO3 as follows:

2CrCl3 + 3Na2CO3 → Cr2(CO3)3(s) + 6NaCl

Where 2 moles of CrCl3 react with 3 moles of Na2CO3 to produce 1 mole of Cr2(CO3)3 -The precipitate-

To solve this question we need to find the moles of CrCl3 added. With the chemical equation we can find the moles of Na2CO3 and its mass as follows:

Moles CrCl3:

520mL = 0.520L * (0.224mol/L) = 0.116 moles CrCl3

Moles Na2CO3:

0.116 moles CrCl3 * (3 mol Na2CO3 / 2mol CrCl3) = 0.175 moles Na2CO3

Mass Na2CO3 -Molar mass: 105.99g/mol-

0.175 moles Na2CO3 * (105.99g/mol) = 18.5g Na2CO3

Answer:

Which of the following pairs lists a substance that can neutralize Ca(OH)2 and the salt that would be produced from the reaction?

HCl and CaCl2

HClO and CaHClO

H2O and Ca(OH)3

H3PO4 and Ca(PO3)2

Explanation:

The given substance is Ca(OH)2 which is a base.

To neutralise a base an acid is required.

Among the given options,

HCl and H3PO4 are the acids.

The salts foremd when calcium hydroxide reacts with the respective acids are CaCl2 and Ca3(PO4)2.

But among the given options, only the forst option that is

HCl and CaCl2 shows the correct formulas.

Hence, the answer is first option.

Answer:

HCl and CaCl2

Explanation:

Answer:

See explanation

Explanation:

Calcium carbide reacts with water to yield acetylene gas and calcium hydroxide as follows;

CaC2(s)+2H2O(g)⇋Ca(OH)2(s)+C2H2(g)

This now shows us that the equation as written in the question is wrong. Since the equation for the reaction of calcium carbide and water as shown in the question is wrong, the equation can not be balanced.

Answer:

ethene

Explanation:

The chemical compound acetylene (systematic name: ethyne) has the formula C2H2. It's a hydrocarbon and the most basic alkyne. Because its two carbon atoms are linked together in a triple bond, acetylene is unsaturated as an alkyne.And the ending of acetylene has ene which indicates that it's an alkene .And the ending of acetylene has ene which indicates that it's an alkene.

Answer: i think it is Ethyne

Explanation: because another name for Acetylene is Ethyne which is commonly known

Answer:

liter

Explanation:

I think liter because it is not listed as a SI unit

Answer:

[tex]{ \bf{d). \: { \tt{litre}}}}[/tex]

Answer:

Potassium

Explanation:

To solve this question we need to find, as first, the average atomic mass of the element knowing that is defined as the sum of the masses of each isotope times their abundances. For the element X:

Average atomic mass:

38*0.0967 + 39*0.7868 + 40*0.1134 + 41*0.0031

= 39.02g/mol

The atom that has the average atomic mass closest to 39.02g/mol is Potassium, K = 39.10g/mol.

Answer:

To determine the number of atoms of Boron that are present within 3.61 grams of Boron Trifluoride, it would be best to convert the grams to moles of the compound and then after that use the Avogadro's number to determine the number of molecules and then use the 1 to 3 ratio to determine the total number of Boron atoms.

Answer:

Explanation:

Why is there a star * behind the question.

CaCl2

Al2(SO4)3

NaOH

Answer:

Si.

Explicación:

Si un oficial de policía está controlando la velocidad en la carretera y dispara al vehículo con una pistola de radar. El policía mide la velocidad media del coche con esta pistola de radar. Una pistola de radar es un dispositivo que se utiliza para medir la velocidad de los objetos en movimiento que fue inventado por Bryce K. Brown en el año de 1954. La pistola de radar se utiliza con fines policiales para calcular la velocidad de los vehículos en movimiento.

Answer:

i believe energy is your answer here

Answer:

2HCl → H2 + Cl2 = decomposition

NaF + KBr → NaBr + KF = double replacement

Mg + MnCl2 → Mn + MgCl2 = single replacement

2Na + 02 → Na2O2 = combination

Explanation:

A chemical reaction involves the conversion of one or more substances called REACTANTS into other substances called PRODUCTS. There are different types of reactions depending on how it occurs, they include:

- Combination or synthesis reaction is a type of reaction in which two or more elements combine to form a single product. Example is:

2Na + 02 → Na2O2

- Single replacement is a type of reaction where one element is replaced by another in a compound or molecule. Example below shows that Manganese (Mn) is replaced by magnesium (Mg):

Mg + MnCl2 → Mn + MgCl2

- Double replacement is a type of reaction where two elements are replaced by other elements at a time. Example is:

NaF + KBr → NaBr + KF

- Decomposition is a type of reaction in which one molecule or compound is broken down into two or more products. Example is:

2HCl → H2 + Cl2

Answer:

the answer would be d. usually dull in appearance

Explanation:

because brittle bendable and poor conductor of heat and electricity are all for the non-metals

Answer:

C !!

Explanation:

hope this helps! usually people classify metals based on if they can conduct heat or electricity

The international system of units is known as SI and is a metric system. Mostly used as a system of measurement. It is used in science, technology, and nearly in every part of the country. The system includes coherent units known as derived units.

Hence the option B is correct.

Learn more about the frequently used in chemical calculations.

brainly.com/question/26120603.

Answer:

The liquid left after crystallization is called Residue

C. Yes, if each sample contains 6.02 x 10²³ atoms.

Answer:

Balancing equations

1

[tex]4Na + O_{2} -> 2Na_{2}O[/tex]

Answer: The answer is D:

Answer:

The answer is Option D

here's your answer hope this will help